This invention relates to a critical care hospital bed that is especially adapted to be used with a mobile radiographic/fluoroscopic unit which is usually referred to as a C-arm or C-arm unit.
A C-arm is a real time fluroroscope used to provide images of a patient's chest area. The apparatus has an arm that is shaped like a C and has an X-ray tube at the upper free end and a receiver image intensifier at the lower end. The C-arm is supported at the end of a cantilever beam which in turn is supported on a mobile base. The C-arm is rolled to a patient's critical care room and is slid around the patient's bed with the receiver underneath the patient and the X-ray tube over the patient. With the C-arm in place and a monitor available for the cardiologist's viewing, the cardiologist can observe, in real time, the movement of surgical devices that are inserted into the patient's heart from various branches of the patient's cardiovascular system.
The invention described herein relates to an improvement in the critical care bed that is used with the C-arm to provide the capability of obtaining images of the patient's chest area over a greater area than has been possible heretofore.
A state of the art critical care bed is disclosed in U.S. Pat. No. 4,751,754. The bed of that patent has, as its base, an elongated central backbone supported on bars at each end, the bars having casters at their ends. A two-bar cantilever support for the bed is mounted at its lower end to one end of the backbone. It is inclined upwardly and is mounted at its upper end to a bracket located at about the center of the bed. The cantilevered support opens up one end of the bed--in this case the head end of the bed--for the insertion of the lower end of the C-arm.
The bed has a rectangular bed frame and overlying it a patient support consisting of four rectangular frames that are pivoted together to enable adjustment of the position of the patient on the bed. The four rectangular frame members define and support a head panel, a seat panel, a thigh panel and a leg panel. The head panel has a translucent center portion which is about 18.times.30 inches in dimensions. Surrounding the translucent portion are opaque support elements projecting laterally outward from the 18 inch translucent center of the head panel, thus creating the normal bed width of 34 inches. Alongside the head and leg panels are head guards and foot guards that project above the mattress on each side of the bed to keep the patient from inadvertently sliding out of the bed.
The bed and guards limit the movement of the C-arm over the bed and as a result, the beam from X-ray tube to receiver cannot be moved to the center of the complete translucent area of the head panel. As a consequence, it is necessary to shift the patient before or during a procedure to one side of the bed so that the invasive surgical implement can be viewed as it passes through arteries into the patient's heart. The C-arm is obstructed by the head guard that is mounted alongside the head panel. The C-arm would also be obstructed by engagement with the side edge of the bed even if the head guard is removed.
The lower end or receiver portion of the C-arm is further obstructed by the backbone's extending down the center of the base below the bed. The upper surface of the backbone is about 8 inches off the floor. The receiver for the C-arm projects downwardly from the end of the C-arm. Somehow the receiver must clear the backbone in order for the receiver to pass over to the center of the bed. In practice, the bed has been raised by swinging the cantilever support upwardly until there can be clearance between the lower end of the C-arm and the backbone as the C-arm is brought into position over the patient. The raising of the bed means that the patient is going to be at an uncomfortable level for the cardiologist so that the cardiologist may even be required to stand on a stool in order to perform the surgical procedures that are monitored by the C-arm.